Short wave tuned circuit arrangement



Dec. 21, 1943.

P. D. ZOTTU SHORT. WAVE TUNED CIRCUIT ARRANGEMENT Original Filed Jan.21, 1937 2 Sheets-Sheet l 24 22 11 za Z7 /Z8 IEF INVENTQR Paul B ZotiuATTORNEY Dec. 21, 1943. p D, ZOTTU 2,337,219

SHORT WAVE TUNED CIRCUIT ARRANGEMENT Original Filed Jan. 21, 1937 2Sheets-Sheet 2 .l'npuf fube INVE NTOR Pcxifflu BY MM ATTORNEY PatentedDec. 21, 1943 SHORT WAVE TUNED CIRCUIT ARRANGEMENT Paul D. Zottu,Richmond, Va., assis'nor to Radio Corporation of America, a corporationof Delaware Original application January 21, 1987, Serial No.

121,498, now Patent No. 2,222,644, dated November 26, 1940. Divided andthis application May 29, 1940, Serial No. 337,798

16 Claims.

This invention relates to ultra short wave radio circuits and is adivision of my copending application, Serial No. 121,498, filed January21, 1937, Patent No. 2,222,644, granted November 26, 1940. The primaryobject of the invention is to provide novel constructions of short waveresonator circuits and novel uses therefor, in associated electrondischarge device arrangements.

In the accompanying drawings:

Fig. 1 shows, by way of example, one form of metallic resonator circuitused as a frequency controlling element of an oscillation generator;

Fig. 2 illustrates another form of construction of a short waveresonator used as the frequency control element or an electron dischargedevice oscillator wherein the oscillator per se is contained within theouter conductor of the line;

Fig. 2a is a perspective view of the circuit of Fig. 2, partlydisassembled to illustrate the mechanical construction of the resonatorand circult; and

Fig. 3 illustrates the use of a short wave resonator as an impedancecoupling element between two stages of a radio frequency amplifier.

Fig. 1 illustrates the use of a novel form of a tuned oscillatorycircuit used as a frequency controlling and feed back arrangementbetween the input and output electrodes of an electron discharge deviceoscillator. In this case, the oscillatory circuit is in the form of aconcentric line and comprises an outer conductor formed of two sections22 and 23 which are capacitively coupled together through an insulatingring 24, both sections being slidable over the inner conductor overelectrically conducting bearings 25 and 26. The inner conductor alsoconsists of two sections 21 and 28 which extend in the same straightline, the adjacent ends of rods 21 and 28 of the inner conductor beingcapacitively coupled together while the other ends are fastened to asuitable support comprising an insulated U-shaped element 29. Theoscillation generator arrangement, shown by way of example as a triode38, has its control electrode connected over a sliding joint to one ofthe elements 21 while its output anode electrode is similarly connectedto the other element 28 of the inner conductor, the filament beingconnected on one side to section 22 and on the other side through asuitable polarizing battery to the other section 23. It will thus beobserved that the control and anode electrodes of the oscillator 38 aresuitably insulated from one another for direct current potential,although the entire assembly of concentric circuits 22, 23, 21, 28 forma single tank circuit. The proper value of excitation may be obtained byadjusting the position of the lead 3| over the length of rod 21,, whilethe proper impedance presented to the output circuit of the electrondischarge device 30 can be obtained by slidably adjusting the lead 32over the length of the rod 28.

At ultra high frequencies where the lengths of the leads 3| and 32 aredesired to be at a minimum and fixed, the excitation of the grid can bevaried not by moving the conductor 3| but by moving the entire outerconductor, consist-'- ing of 22, 23 and 24, over the length of innerconductor elements 21 and 28. The bearings 25 and 28 which permit theconductive connection between the outside cylinder and the innerconductor enable such a movement to be made with,-

out disturbing the connections to the electrodes of the electrondischarge device. In this case, of course, the leads from the filamentof tube to to both cylindrical elements 22 and 23 .of the outerconductor should be of sufficient length to enable such an adjustmentwithout breaking the connections to the outer conductor of the tunedcircuit. The capacity between the two metallic rods 21 and 28 of theinner conductor can be varied in any suitable fashion, such as byadjusting one of the rods 21 or 28 or both with respect to one anotherfrom a point external of the tuned concentric circuit, such as by handleor knob 33 which is mechanically linked to the rod 28. Y

Where desired, the radio frequency filament return leads need not befixedly fastened to the outer conductor but may be arranged in slidingcontact fashion so that the electron discharge device and leadconnections remain fixed while the outer conductor slides over the innerconductor. Such an arrangement is shown in Figs. 2 and 2a which now showthe electron discharge device 38 located within the outer conductor, thegrid and anode being permanently connected to suitable points on the tworods 21 and 28 of the inner conductor. The tube 30 in this figure is ofthe indirectly heated type, each leg ofthe filament and heater beingby-passed to the outer conductor which may be at ground or zero radiofrequency potential, by means of condensers comprising suitably spacedand insulated connections 33' and 34 which, although fixed with respectto one another, permit the outer conductor of the tuned concentric lineto make a wiping contact over the lengths of the two outer connections33'. This will be more apparent from an inspection of Fig. 2a, whichshows the construction of Fig. zsomewhat disassembled. The tunedconcentric line of Fig. 2 also differs from that of Fig. 1 by having theisolating condenser of the outer conductor (indicated generally as 24 inFig. 1) at one of the'extreme ends of theline. In Fig. 2, this isolatingcondenser merely consists of end plate 35 fastened to the outerconductor but separated by means of mica spacers from a pair of flanges38 which are in intimate contact with the rod 28 of the inner conductor.Instead oi. using bearings, such as 25 and 28 shown in Fig. 1, there areprovided at each end of the line circuit of Fig. 2 suitable sliding fitswhich enable the outer conductor to be varied as a unit over themetallic rods 21 and 28 comprising the inner conductor, in the samefashion as the outer conductor of Fig. 1 is variable over its innerconductor. These sliding fits comprise, in a preferred embodiment, tightcylindrical metallic shields which are slit longitudinally at severalpoints in their periphery for the purpose of providing a firm springycontact with the rods 21 and 28 constituting the inner conductor.

Variation of the capacity between rods 21 and 28 is here obtained byvariation in the projecting length of a plug 31 which is movable insuitably cut-out apertures in the inner conductors 21 and 28, as shown,and movable in response to variation of knob 33.

Energy may be taken from the tuned concentric line of Figs. 2 and 2a bymeans of a suitable sleeve 38 which contacts with either rod 21 or 28and is movable over their lengths by virtue of a metallic rod 38 whichextends out from the outer conductor through a slit running along theaxes of the inner and outer conductors. Rod

39 is, of course, insulated from the outer conductor as it passesthrough the slit, either by means of an insulating material or by meansof the air space between the rod 33 and outer conductor.

When it is desired to obtain a greater output from the tuned concentricline circuits of Figs. 1 and 2 than is possible by the use of a singleelectron discharge device, there may be employed a plurality of electrondischarge devices placed around the tuned line circuit in identicallythe same manner as shown in either Figs. 1 or 2. In the case of Fig. 2,of course, the electron discharge devices would be located in theinterior of the tuned circuit and, preferably, symmetrically disposedaround the inner surface of the outer conductor with respect to theinner conductor.

Fig. 3 illustrates a tuned concentric line of a type very similar tothat shown in Fig. 1 as an impedance coupling element between two stagesof an amplifier. It should be noted that whereas the circuit of Fig. 1shows this line' as a frequency controlling and feed back path for anoscillation generator. the line of Fig. 3 is an impedance couplingelement between the output electrodes of one stage and the inputelectrodes of another stage. In this last figure, the output electrodesof one stage are connected to one rod and one outer cylinder of theinner and outer conductors of the line, respectively, while the inputelectrodes of the other stage are connected to the other rod and theother cylinder of the inner and outer conductors of the line,respectively. Here again, although the outer conductor is shown slit inthe center in the same manner shown in Fig. 1, if desired the outerconductor may consist of a single cylinder which is insulated from theinner conductor at one end, as shown in Fig. 2, the essentialrequirement being that the outer conductor be insulated from at leastone of the rods of the inner conductor at some point in its length. Formechanical simplicity, the cylinders 22 and 23 of the outer conductorare here shown capacitively coupled together through a spaced concentricmetallic cylinder 48, instead of by means of flanges as shown in Fig. 1.

It is to be distinctly understood that the invention is not limited tothe precise arrangements shown and described, since variousmodifications may be made without departing from the spirit and scopethereof.

What is claimed is:

1. An impedance coupling element between an input and an output circuit,comprising a pair of concentric lines placed end to end, each line ofsaid pair having an inner and an outer conductor coupled together at theend remote from the other line, means for capacitively coupling saidinner conductors together, and means for capacitively coupling saidouter conductors together, whereby said pair of concentric lines takentogether form an electrical resonator, said input circuit being coupledto one of said lines, and said output circuit being coupled to the otherof said lines.

2. A tuned circuit comprising a concentric line having straight innerand outer conductors coupled together, said inner and outer conductorsbeing each physically separated into two portions, which two portionsare capacitively coupled together at their adjacent ends, the twoportions of the outer conductor being movable as a unit over the outersurface of said inner conductor.

3. A tuned circuit comprising a concentric line having inner and outercoupled conductors, said inner and outer conductors being eachphysically separated into two portions, which two portions arecapacitively coupled together at their adjacent ends, the other ends ofsaid outer conductor portions being in conductive contact with differentportions of the inner conductor and slidably movable thereover.

4. A tuned circuit comprising a concentric line having inner and outercoupled conductors, said inner conductor being separated into two 00-axially arranged portions whose adjacent ends are capacitively coupledtogether, means for varying the capacity of said two portions, means forcoupling said outer conductor to said two portions, said means beingslidable over the lengths of said two portions.

5. The combination with a circuit as defined in claim 4, of an inputcircuit coupled between one portion of the inner conductor and saidouter conductor, and an output circuit coupled between the otherportions of said inner conductor and outer conductor.

6. The combination with a circuit as defined in claim 4, ofan inputcircuit coupled between one portion of said inner conductor and saidouter conductor, and an output circuit coupled between the other portionof said inner conductor and said outer conductor, the connections fromsaid input and output circuits to said portions being adjustable overthe lengths thereof.

7. In combination, an ultra high frequency tuned oscillatory circuit inthe form of a metallic surface of revolution, said surface of revolutionbeing divided into two similarly constructed and symmetrically locatedcylindrically shaped parts capacitively coupled together at theiradjacent edges by spaced flanges, a lumped capacitor located in theinterior and substantially in the center of said surface of revolutionand having diflerent plates directly connected from a direct currentstandpoint to opposite points on said two parts by inductance in theform of rods.

8. In combination, an ultra high frequency tuned oscillatory circuit inthe form of a metallic surface of revolution, said surface of revolutionbeing divided into two similarly constructed and symmetrically locatedcylindrically shaped parts capacitively coupled together at theiradjacent edges by spaced flanges, a lumped capacitor located in theinterior and substantially in the center of said surface of revolutionand having different plates directly connected from a direct currentstandpoint to opposite points on said two parts by inductance in theform of rods, said rods being arranged in the same straight line andpositioned along the axis of said surface, said lumped capacitorcomprising a plurality of spaced metallic plates located between theadjacent ends of said rods.

9. In combination, an ultra high frequency tuned oscillatory circuit inthe form of a metallic surface of revolution, said surface of revolutionbeing divided into two similarly constructed and symmetrically locatedparts capacitively coupled together at their adjacent edges by spacedflanges, a lumped capacitor located in the interior and substantplly inthe center of said surface of revolution and having different platesdirectly connected from a direct current standpoint to opposite pointson said two parts by inductance in the form of rods.

10. In combination, an ultra high frequency tuned oscillatory circuit inthe form of a metallic surface of revolution, said surface of revolutionbeing divided into two similarly constructed and symmetrically locatedparts capacitively coupled together at their adjacent edges by spacedflanges, a lumped capacitor located in the interior and substantially inthe center of said surface of revolution and having different platesdirectly connected from a direct current standpoint to opposite pointson said two parts by inductance in the form of rods, said rods beingarranged in the same straight line and positioned along the axis of saidsurface, said lumped capacltor comprising a plurality of spaced metallicplates located between the adjacent ends of said rods.

11. In combination, an ultra high frequency tuned oscillatory circuit inthe form of a metallic surface of revolution, said surface of revolutionbeing divided into two similarly constructed and symmetrically locatedparts capacitively coupled together at their adjacent edges by spacedflanges, a lumped capacitor located in the interior and substantially inthe center of said surface of revolution and having different platesdirectly connected from a direct current standpoint to opposite pointson said two parts by inductance in the form of rods, means for couplingsaid surface of revolution to said rods, said means being slidable oversaid rods.

12. In combination, an ultra high frequency tuned oscillatory circuit inthe formof a metallic surface of revolution, said surface of revolutionbeing divided into two similarly constructed and symmetrically locatedparts capacitively coupled together at their adjacent edges, a

- lumped capacitor located in the interior and subnected from a directcurrent standpoint to opposite points on said two parts by inductance inthe form of rods, an electron discharge device having an anode, acathode and a control electrode, connections from said anode and controlelectrode to difierent ones of said rods, and a connection from saidcathode to said surfaceof revolution.

13. In combination, an ultra high frequency tuned oscillatory circuit inthe form of a metallic surface of revolution, said surface of revolutionbeing divided into two similarly constructed and symmetrically locatedparts capacitively coupled together at their adjacent edges, a lumpedcapacitor located in the interior and substantially in the center ofsaid surface of revolution and having different plates directlyconnected from a direct current standpoint to opposite points on saidtwo parts by inductance in the form of rods, said rods being arranged inthe same straight line and positioned along the axis of said surface,said lumped capacitor comprising a plurality of spaced metallic plateslocated between the adjacent ends of said rods, an electron dischargedevice having an anode, a cathode and a control electrode, connectionsfrom said anode and control electrode to different ones of said rods,and a connection from said cathode to said surface of revolution.

14. In combination, a tuned circuit comprising a concentric line havinginner and outer coupled conductors, said inner and outer conductorsbeing each physically separated into two portions, which two portionsare capacitively coupled together at their adjacent ends, the other endsof said outer conductor portions being coupled with different portionsof the inner conductor, an electron discharge device having an anode, acathode and a control electrode, connections from said anode and controlelectrode to different portions of said inner conductor and a connectionfrom said cathode to said outer conductor. 4 p

15. In combination, a tuned circuit comprising a concentric line havinginner and outer coupled conductors, said inner and outer conductorsbeing each physically separated into two portions, which two portionsare capacitively coupled together at their adjacent ends, the other endsof said outer conductor portions being coupled with different portionsof the inner conductor, an electron discharge device having an anode, acathode and a control electrode, con nections from said anode andcontrol electrode to different portions of one of said conductors ofsaid tuned circuit, and a connection from said cathode to the otherconductor of said tuned circuit.

16. An ultra-high frequency device, comprising a coaxial line havinginner and outer members short circuited at both ends, said innerconductorbeing open intermediate its ends, capacitive loading meansinterposed in said inner conductor where said inner conductor is open,an anode connected to said inner conductor at one side of the pointwhere said inner conductor is open, a grid connected to the innerconductor at the other side of said point and positioned to cooperatewith said anode, an emissive cathode positioned to cooperate with saidgrid and said anode to form a triode, the impedances of said triodebeing matched to the impedances of said coaxial line at the point wheresaid cathode, grid and anode are respectively connected.

PAUL D. ZO'I'ITU.

